Cadmium removal by lactic acid bacteria

Abstract

Diet is the major source of cadmium for the non-smoking population. Currently, no method is available to remove cadmium from food products. Because the content of cadmium in the food is likely to continue to rise in the future, a new method for decontaminating foods is urgently needed. We assessed the ability of safe food grade lactic acid bacteria (LAB) to remove cadmium from an aqueous solution. At a concentration of 10 μg/l up to 70% could be removed within 5 min, and up to 90% after 1 hr. At a concentration of 1000 μg/l between 5 and 30% was removed after 5 min and between 20 ad 55% after 1 hr. Heat-treatment of the bacteria significantly enhanced the removal of Cd at 10 and 100 μg/l, but not at 1000 μg/l. Increased temperature (37°C), prolonged incubation (24 hr) and higher bacterial concentrations (5 x 10 9 bacteria/ml) were found to increase the removal of Cd. LAB were shown to remove cadmium in a strain, temperature and concentration dependent manner. The results indicate that food grade LAB may provide a much needed means for decontamination of liquid foods. The practical feasibility of this approach deserves to be further investigated considering the importance of Cd removal from food.